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APAM Spring Conference 4/21/15Aaron Price –
Pete Capon – Rieth-Riley Construction Co.
NAPA Scan Tour - Japan
Presentation Outline
1. Introduction-Why visit Japan?2. R &D3. Mix Design (High RAP)4. Mix Production & RAP Management5. Construction6. Take-Aways
Broad Take-Aways1. Strong Quality Focused Culture2. Different Industry Structure than the US3. Pro-Recycling Government
Policies/Contractor Philosophy4. Mixture Production Processes are different
than the US5. High Degree of Contractor R&D/Innovation
Why Visit Japan? The National Asphalt Pavement
Association (NAPA) learned that, Japan averages 45%+ RAP in their asphalt mixtures.
NAPA organized the Scan Tour with Japanese counterparts to facilitate this technology transfer
TaiseiTotec Plant Visit
US Delegation
Size and scale compared to U.S. Japan has roughly half
the population (126 million) and only about 4% of the land area of the U.S. Over 1,000 plants
producing 50 million tons Unites States production
is 350 million tons with about 3,000 Plants
General Observations Blend of old traditions and new technology In some specific areas – the Japanese would
appear to be more advanced than the US but in many ways are somewhat behind the US
Lower production rates (75-150 TPH typical) 5 Contractors perform most of the work Typical projects are 2000 tons
Motivation - Recycling in Japan Government mandate
Japanese concluded in 1992 that RAP mixtures were as good as virgin mixes
Limited resources Virgin aggregate comes from
Russia Oil is imported RAP is a valuable resource
Japanese Asphalt Mix Products
Research and Development
R & D Observations Contractors have extensive research labs High level of trust between industry and agency Warranties – Rutting (primary focus) and Cracking Empirical emphasis – observation based Performance Based Specifications Just starting to look at WMA technologies High RAP Mixtures (with and w/o foamed
rejuvenators)
Innovation – High RAP Up to 70 % RAP Use of Rejuvenators RAP materials made
into an HMA-like mix Silo time for RAP matl. High RAP Mixtures are
a Manufacturing Process
Innovation–Pavement Color/Temp
Innovation
OGFC Rutting/Wheel Tracking Tests
Innovation
Dual Layer Paving
WMA
Pavement
Management
Innovation - Double Layer Porous
Asphalt Paving Project
High RAP Mix Design
Mix Design Marshall Mix Design Pen/Viscosity Grade
Binders Polymers are utilized Mix Designs appear to
be “richer” than non-regressed SP mixes
Performance tests
Mix Design – Randy West (NCAT) Japan has established simple mix tests to evaluate
mix designs Those tests are the indirect tensile modulus (peak
stress/deformation) and a wheel tracking test (dynamic stability)
This allows the mix designer (contractor) to be innovative in developing combinations of materials (e.g. RAP, softer virgin binders, and rejuvenators) to meet the mix design criteria (blending charts).
RAP Parameters RAP binder must have
a 20+ penetration and 3.8%+ AC or it can/will be discarded
Fractionated into 2 or 3 sizes to develop proper blend
Rejuvenators The key to using high
RAP mixtures is the introduction of a rejuvenating agent to condition the RAP
It softens and activates the hardened – it takes time, 1-3 hours in the silo after mixing
Rejuvenators Proprietary! One identified as
paraffinic oil Many options
Mix Types They keep mix
types to a minimum and simple descriptions
High RAP Examples: Batched a virgin mix along with 45% and 60% RAP mixtures
Asphalt Plant in Japan
High RAP Mixture Production
Recycling Methods in Asphalt Plants
68.8
17.7
13.5
Plant Types
Parallel HeatIn Direction - Not VisitedDram Mixing - Not Visited
Maeda Road & TaiseiRotec Plants Parallel Heat System Batch plant producing
180 tons/hour 270,000 tons/year
32 employees with dorm so that mix available 24 hours
Dust and Odors are tightly controlled
Parallel Heat System – Two Dryer
Most common plant type (68.8%) and the type we visited while on our tour
Parallel dryers… Parallel for recycle and Counter-Flow for virgin materials
Material Flow RAP is heated (300º-320º F) in the dryer/mixer
(Parallel flow, indirect heating) Rejuvenator added to RAP in dryer/mixer or pugmill,
then transferred to surge bin/silo (1-3 hours hold time)
Virgin materials dried and moved over screens (typical)
RAP mixture is mixed with virgin aggregates and AC in the mixer
RAP Dryer/Mixing Drum
Virgin Matls. - Clean and Covered
Handled and processed similar to the United States
Covered cold feed bins to maintain low moisture content
Binders can be blended in-line if needed
Processing RAP Most of the RAP we
observed was delivered in pieces (milling/cutting is performed but not as common as in the US)
Delivered to the asphalt plant for processing
Crushed, sized & screened
Processing RAP - Cont. RAP is fractionated
much like it is here in the U.S.
The RAP processing facility we visited was indoors (strict dust and pollution requirements)
RAP Indoor Processing Facility
Managing RAP Materials Covered processing
and bin storage They keep RAP dry…
reported at 1.5%-2.0% moisture
RAP is tested for gradation, binder % & penetration grade
Asphalt Paving Project
Construction
Trucking Operations
Paving Operations
Compaction
Excellent workmanship
Takeaways
Broad Take-Aways1. Strong Quality Focused Culture2. Different Industry Structure than the US3. Pro-Recycling Government
Policies/Contractor Philosophy4. Mixture Production Processes are different
than the US5. High Degree of Contractor R&D/Innovation
Take-Aways – Specifics A Few Contractors perform much of the work to High RAP mixes - indirectly dried/heated (320º F) & mixed w/rejuvenators
(RAP mix silo time 1-3 hrs) - the process could work in the US in the future RAP Mix (rejuvenators) + Virgin Matls. = High RAP RAP is highly managed (many times processed indoors, fractionated, stored in
bunkers, etc.) Mix production is a manufacturing process RAP mixes can perform as well as virgin mixes High level of trust between industry and agency Warranties – Rutting (primary focus) and Cracking Empirical emphasis – Observation based, if it works don’t fix it
Aaron Pricel Cadillac Asphalt l [email protected]
Pete Capon l Rieth-Riley Construction Co., Inc. l [email protected]
Questions?
